[thirdparty/man-pages.git] / man3 / gsignal.3

.\" Copyright (C) 2002 Andries Brouwer <aeb@cwi.nl>
.\"
.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" %%%LICENSE_END
.\"
.\" This replaces an earlier man page written by Walter Harms
.\" <walter.harms@informatik.uni-oldenburg.de>.
.TH GSIGNAL 3  2020-04-11 "" "Linux Programmer's Manual"
.SH NAME
gsignal, ssignal \- software signal facility
.SH SYNOPSIS
.nf
.B #include <signal.h>
.PP
.B typedef void (*sighandler_t)(int);
.PP
.BI "int gsignal(int " signum );
.PP
.BI "sighandler_t ssignal(int " signum ", sighandler_t " action );
.fi
.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.PP
.BR gsignal (),
.BR ssignal ():
    Since glibc 2.19:
        _DEFAULT_SOURCE
    Glibc 2.19 and earlier:
        _SVID_SOURCE
.SH DESCRIPTION
Don't use these functions under Linux.
Due to a historical mistake, under Linux these functions are
aliases for
.BR raise (3)
and
.BR signal (2),
respectively.
.PP
Elsewhere, on System V-like systems, these functions implement
software signaling, entirely independent of the classical
.BR signal (2)
and
.BR kill (2)
functions.
The function
.BR ssignal ()
defines the action to take when the software signal with
number
.I signum
is raised using the function
.BR gsignal (),
and returns the previous such action or
.BR SIG_DFL .
The function
.BR gsignal ()
does the following: if no action (or the action
.BR SIG_DFL )
was
specified for
.IR signum ,
then it does nothing and returns 0.
If the action
.B SIG_IGN
was specified for
.IR signum ,
then it does nothing and returns 1.
Otherwise, it resets the action to
.B SIG_DFL
and calls
the action function with argument
.IR signum ,
and returns the value returned by that function.
The range of possible values
.I signum
varies (often 1\(en15 or 1\(en17).
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR gsignal ()
T}	Thread safety	MT-Safe
T{
.BR ssignal ()
T}	Thread safety	MT-Safe sigintr
.TE
.sp 1
.SH CONFORMING TO
These functions are available under AIX, DG/UX, HP-UX, SCO, Solaris, Tru64.
They are called obsolete under most of these systems, and are
broken under
.\" Linux libc and
glibc.
Some systems also have
.BR gsignal_r ()
and
.BR ssignal_r ().
.SH SEE ALSO
.BR kill (2),
.BR signal (2),
.BR raise (3)
Commit	Line	Data
	1	.\" Copyright (C) 2002 Andries Brouwer <aeb@cwi.nl>
	2	.\"
	3	.\" %%%LICENSE_START(VERBATIM)
	4	.\" Permission is granted to make and distribute verbatim copies of this
	5	.\" manual provided the copyright notice and this permission notice are
	6	.\" preserved on all copies.
	7	.\"
	8	.\" Permission is granted to copy and distribute modified versions of this
	9	.\" manual under the conditions for verbatim copying, provided that the
	10	.\" entire resulting derived work is distributed under the terms of a
	11	.\" permission notice identical to this one.
	12	.\"
	13	.\" Since the Linux kernel and libraries are constantly changing, this
	14	.\" manual page may be incorrect or out-of-date. The author(s) assume no
	15	.\" responsibility for errors or omissions, or for damages resulting from
	16	.\" the use of the information contained herein. The author(s) may not
	17	.\" have taken the same level of care in the production of this manual,
	18	.\" which is licensed free of charge, as they might when working
	19	.\" professionally.
	20	.\"
	21	.\" Formatted or processed versions of this manual, if unaccompanied by
	22	.\" the source, must acknowledge the copyright and authors of this work.
	23	.\" %%%LICENSE_END
	24	.\"
	25	.\" This replaces an earlier man page written by Walter Harms
	26	.\" <walter.harms@informatik.uni-oldenburg.de>.
	27	.TH GSIGNAL 3 2020-04-11 "" "Linux Programmer's Manual"
	28	.SH NAME
	29	gsignal, ssignal \- software signal facility
	30	.SH SYNOPSIS
	31	.nf
	32	.B #include <signal.h>
	33	.PP
	34	.B typedef void (*sighandler_t)(int);
	35	.PP
	36	.BI "int gsignal(int " signum );
	37	.PP
	38	.BI "sighandler_t ssignal(int " signum ", sighandler_t " action );
	39	.fi
	40	.PP
	41	.in -4n
	42	Feature Test Macro Requirements for glibc (see
	43	.BR feature_test_macros (7)):
	44	.in
	45	.PP
	46	.BR gsignal (),
	47	.BR ssignal ():
	48	Since glibc 2.19:
	49	_DEFAULT_SOURCE
	50	Glibc 2.19 and earlier:
	51	_SVID_SOURCE
	52	.SH DESCRIPTION
	53	Don't use these functions under Linux.
	54	Due to a historical mistake, under Linux these functions are
	55	aliases for
	56	.BR raise (3)
	57	and
	58	.BR signal (2),
	59	respectively.
	60	.PP
	61	Elsewhere, on System V-like systems, these functions implement
	62	software signaling, entirely independent of the classical
	63	.BR signal (2)
	64	and
	65	.BR kill (2)
	66	functions.
	67	The function
	68	.BR ssignal ()
	69	defines the action to take when the software signal with
	70	number
	71	.I signum
	72	is raised using the function
	73	.BR gsignal (),
	74	and returns the previous such action or
	75	.BR SIG_DFL .
	76	The function
	77	.BR gsignal ()
	78	does the following: if no action (or the action
	79	.BR SIG_DFL )
	80	was
	81	specified for
	82	.IR signum ,
	83	then it does nothing and returns 0.
	84	If the action
	85	.B SIG_IGN
	86	was specified for
	87	.IR signum ,
	88	then it does nothing and returns 1.
	89	Otherwise, it resets the action to
	90	.B SIG_DFL
	91	and calls
	92	the action function with argument
	93	.IR signum ,
	94	and returns the value returned by that function.
	95	The range of possible values
	96	.I signum
	97	varies (often 1\(en15 or 1\(en17).
	98	.SH ATTRIBUTES
	99	For an explanation of the terms used in this section, see
	100	.BR attributes (7).
	101	.TS
	102	allbox;
	103	lb lb lb
	104	l l l.
	105	Interface Attribute Value
	106	T{
	107	.BR gsignal ()
	108	T} Thread safety MT-Safe
	109	T{
	110	.BR ssignal ()
	111	T} Thread safety MT-Safe sigintr
	112	.TE
	113	.sp 1
	114	.SH CONFORMING TO
	115	These functions are available under AIX, DG/UX, HP-UX, SCO, Solaris, Tru64.
	116	They are called obsolete under most of these systems, and are
	117	broken under
	118	.\" Linux libc and
	119	glibc.
	120	Some systems also have
	121	.BR gsignal_r ()
	122	and
	123	.BR ssignal_r ().
	124	.SH SEE ALSO
	125	.BR kill (2),
	126	.BR signal (2),
	127	.BR raise (3)